Britain and its allies must overcome their misgivings and fight these
murderers wherever they hide until there are no more atrocities

The growing intensity of the conflict between the West and the fanatical followers of Islamic State of Iraq and the Levant (Isil) has been graphically demonstrated by the slaughter in Paris.

The architects of the attacks will no doubt be hoping the mass casualties will place President François Hollande under pressure to end France’s military contribution to the campaign against Isil in Syria. But yesterday, the French government committed to a “merciless response to Isil barbarians”.

This response will have a direct bearing on Britain’s policy for tackling Isil, in particular whether David Cameron will try to win Commons backing for British air strikes in Syria.

The US drone strike that killed Mohammed Emwazi has highlighted the limitations of Britain’s current policy. Although a wide range of intelligence and military assets on both sides of the Atlantic worked together to hunt down “Jihadi John”, the Commons ban on British military operations in Syria meant the assignment had to be handed to our US allies. Indeed, Gen Sir Nick Houghton, the Chief of the Defence Staff, has warned that Britain is “letting down its allies” by confining its military operations to neighbouring Iraq.

So if Cameron really is serious about standing shoulder to shoulder with France and our other key allies, then he must give priority to this thorny issue: winning Commons approval for air strikes in Syria. It would be an important first step towards the defeat of Isil. For a start it would allow RAF Tornadoes and drones to target Isil operatives and positions, rather than having to get the Americans to do our work.

But it would also help coalition commanders as they devise a military strategy. Air power is a vital component, but other assets, such as ground forces, are needed if Western politicians are ultimately to achieve their goal of destroying Isil.

The reluctance of our leaders to commit ground troops means that they have had to rely on local proxies, such as the Kurds and moderate Syrian forces. Until recently, these regional allies have struggled to impress. But just as Western intelligence officials were celebrating the drone strike against Jihadi John, the Kurds announced they had captured the Iraqi town of Sinjar from Isil. The Kurdish success, moreover, was achieved with the backing of coalition air power, which kept Isil fighters pinned down as the Kurds made good their advance.

The success at Sinjar provides a promising military template for defeating Isil. While the West uses its superior intelligence-gathering technology and air power to identify and degrade Isil’s command structure, local militias, supported by specialist land forces, can liberate vital territory from Isil. With proper leadership and co-ordination, and with Britain fully committed to air strikes in Syria, it could yet be the most effective way of preventing further atrocities from being carried out, whether on the streets of Paris or London.